In this paper I describe the work that is currently under way, within the Network of Excellence charged with creating a draft Common Frame of Reference, to draft rules on security over moveable assets. After a brief introduction, I deal with two broad questions: (1) the general aims and scope of the scheme for security interests in the traditional sense (such as possessory and non-possessory pledges or mortgages) and (2) registration and other forms of ‘perfection’ (i.e., ensuring that the security interest will be as fully effective as is possible under the applicable law of insolvency). Professor Veneziano’s paper deals with the enforcement of security interests and the very controversial question of whether transactions that are not traditionally classified as security transactions but that serve the same economic function (such as retention-of-title clauses and finance leases) should be brought within the scheme.